1. Field of Invention
The invention relates to an apparatus and method for severing vegetation. More specifically, the invention relates to an apparatus and method for severing vegetation with focused laser beams projected from a reel type mounted mower unit.
2. Description of the Related Art
One type of mowing device including gasoline powered rotary cutting mowers having cutting blades rotated in a horizontal plane and operated by at least one vertical drive spindle, belts and/or drive shafts, and gearing mechanisms. An example of the prior art is U.S. Pat. No. 4,952,222, issued to Tobias, which discloses a grass cutting device with an electrically activated energy path such as strands of wires between spaced electrodes that intersect blades of grass and sears off the grass tips at the contact points. The strands of wires or electrodes are supported by a support means adapted to rest on or in close proximity to the ground. The device also discloses a method of grass cutting including establishing a grass cutting energy path at a location proximate the ground for severing the upper portions of grass blades. The grass cutting energy path can alternatively includes a laser having a laser beam path directed by generally stationary mirrors to extend the laser beam path horizontally within the mower housing between mirrors at a location parallel to the ground. The laser beam may be diminished in intensity and misdirected by reflections off of vibrating mirrors within the mower housing, and may be deflected by the multitude of wet grass blades or reflective objects within the laser beam path as the beam is directed parallel to the ground between mirrors and reflectors.
Another mowing device is a reel type cutting mower that includes a frame within which is mounted a reel rotating about a horizontal axis, with the rotating reel being cylindrical in shape and having a plurality of curved reel blades on the reel. The rotating curved reel blades pass in close proximity to a bed-knife and cutter bar assembly which spans the cutting unit frame parallel to the reel axis. Grass is sheared as it passes between the reel blade and bed-knife/cutter bar assembly. Reel cutting mowers generally provide a more precise cutting of grass, as utilized for golf course maintenance as walk-behind, riding, and towed grass mowers. A drawback of reel cutting mowers includes jamming with moist grass cuttings as the rotating curved reel blades pass in close proximity to the bed-knife or cutter bar assembly. An addition drawback of reel cutting mowers is that the drive connection and adjustable bed-knife/cutter bar assembly require a multitude of mechanicals parts for proper operation, and require adjustments of numerous parts to attain different cutting heights of the reel cutting assembly.
An example of the prior art for reel cutting units is U.S. Pat. No. 5,822,966, issued to Snell, which discloses an adjustable bed-knife and cutter bar for altering the position and angulation of the bar relative to the rotatable reel blades. The cutter bar is adjustable along the arc on the circumference of the rotatable reel for about two different cutting conditions such as a low angle position for low maintenance types of turf, and a high angle position for high maintenance type of turf. The adjustable bed-knife and cutter bar includes a plurality of parts that are hand-adjusted to attain the preferred angle position of the cutter bar.
A further example of the prior art is U.S. Pat. No. 5,896,734, issued to Chesack et al., which discloses a lawn mower having a rotation drive connection assembly providing a reel shaft with curved blades rotating with the reel shaft. The rotation drive connection assembly includes a plurality of mechanical parts which require hand-adjustment to attain the preferred cutting position of the curved blades.
An example of the prior art for riding grass mowers is U.S. Pat. No. 6,032,441, issued to Gust et al., which discloses a triplex trim mower having two reel-type cutting units in the front of the drive unit, and having a rear reel-type cutting unit attached to the drive unit. The mower utilizes reel-type cutting units operated by mechanical connections, and adjusted in position by a positioning means including at least one hydraulic cylinder under operator command.
The prior reel cutting assemblies are typically mechanically or hydraulically adjustable for cutting height. The prior reel cutting assemblies can be operated at a pre-determined speed of rotation, or the speed of rotation of the cutting blades can be adjusted by the operator depending on the need for precise cutting on golf course greens, or less precise cutting on golf course fairways or rough areas.
Commercial mowers would benefit from a reel cutting apparatus that incorporates a cutting means that includes a minimum of parts and that can increase in rotational speed and/or angle of cutting regardless of the ground speed, as controlled by the operator, with no limitation to the rotational speed of the cutting means. By having an easily adjustable rotational speed and/or angle of cutting, the operator may adjust the reel cutting means during mowing operations without stopping the rotation of the reel cutting means to produce smaller sized clippings for effective cutting and mulching of the vegetation.
A need exists in the vegetation control industry for a rotating reel severing apparatus that cuts vegetation at varying speeds during passage of the rotating reel severing apparatus over the vegetation, that does not generate excess noise, and that includes a minimum of moving parts.
Therefore, it is an object of the present invention to provide at least one laser beam projecting between a transmitter and a receiver along a path which contains vegetation to be severed.
It is another object of the present invention to provide a rotating reel severing means for severing vegetation at appropriate heights above the ground with laser light.
It is another object of the present invention to provide an apparatus having a rotating reel severing means rotatable at increasing speeds in proportion to the speed of the apparatus along the surface covered by vegetation.
It is another object of the present invention to provide an apparatus having a rotating reel severing means that includes a minimum of belts, mechanical connectors, and rotating blades.
It is another object of the present invention to provide an apparatus having a rotating reel severing means that does not generate excess noise and minimizes use of moving blades.
It is another object of the present invention to provide a method for severing vegetation with a rotating reel generating means projecting laser light beams during each rotation of the laser generating means.
It is another object of the present invention to provide a method for severing vegetation with a rotating laser generating means operating at high rotational speeds for improved mulching of the cut vegetation.
A mower for severing vegetation is disclosed with the mower including a reel type laser mower for projecting at least one laser beam between a transmitter and a receiver along a path which contains vegetation to be severed. The reel type laser mower is operable by a user at various ground speeds along a surface covered by vegetation, and includes in one embodiment a rotating laser generating means for projecting and redirecting at least one laser beam along multiple, substantially parallel paths within the mower for severing vegetation contacted by the laser beams. The at least one laser beam is projected between a transmitter and a receiver, and redirected back toward the transmitter within a housing having an opening oriented downwards. The paths of the directed and redirected laser beams are directed horizontally across the opening for contacting and severing vegetation.
A control means is provided to control the speed of rotation of the laser generating means in proportion to the ground speed of the mower. The laser generating means can direct a plurality of laser beams transmitting at different intensities, with each laser beam transmitted across the opening, or, alternatively, angled downwards toward the opening to sever vegetation at different angles during each rotation of the laser beams, thereby creating improved aesthetics for the cut vegetation and improved mulching and decomposition of the vegetation cuttings.